In a variety of fields, there is a growing need for systems and devices (also referred to as personal location systems or personal emergency response systems) that can monitor and/or track the location of an individual or an object. For example, such monitoring is useful in the medical care and assisted living fields, in order to ensure the safety and security of patients (e.g. individuals with autism or Alzheimer's) who may wander outside of a care facility and potentially become lost. Other potential fields include child care, law enforcement and geographically isolated working environments (e.g. mines).
Prior art personal location systems rely mainly on GPS (Global Positioning System) technology, which cannot typically provide indoor location data since GPS is a space-based satellite navigation system that requires an unobstructed line of sight to several GPS satellites in order to provide location information.
Existing personal location systems that provide indoor locating typically rely on complex mesh networks or Wi-Fi and have very high deployment costs. Such systems are not easily scalable for residential-type establishments and require a high level of technical expertise for installation and setup.
Other solutions for indoor locating services make use of a single base station set up within a perimeter (e.g. a building), that can detect when a location device is in or out of communication range. Unfortunately, such prior art solutions cannot identify the specific area (e.g. room) in which the individual is located within the monitored perimeter.
U.S. Pat. No. 7,825,794 describes a patient tracking system in which the patient wears an electronic asset tag having an active mode and a sleep mode. The electronic tag is kept at low power in the sleep mode to conserve power, and power is consumed by the electronic tag when the electronic tag moves out of range of an external transmitter. When the patient moves out of range of a base station for a predetermined period of time, the electronic tag switches on and begins transmitting its coordinates to a terrestrial radio network. The non-portable base station is described as being positioned at a fixed location and powered from the mains. Unfortunately, this system would likely fail during a power outage or power glitch, conditions which would seem to raise false alarms disabling power mode. Furthermore, this system does not provide for any alarm events when the electronic tag has gone beyond the range of the plugged-in base station, nor is this system able to identify a specific area in which the patient is located.
Consequently, there exists a need in the industry for an improved personal location system.